(1) Field of the Invention
The invention relates to a liquid surfactant-containing laundry detergent that contains a specific cellulose derivative as a graying-inhibiting active substance.
The purpose of graying inhibitors is to keep dirt released from the fibers in the context of textile washing suspended in the bath, thus preventing the dirt from redepositing onto the textile. Water-soluble colloids, usually organic in nature, are suitable for this, for example size, gelatin, salts of ethersulfonic acids of starch or of cellulose, or salts of acid sulfuric acid esters of cellulose or starch. Water-soluble polyamides containing acid groups are also suitable for this purpose. Soluble starch preparations, and starch products other than those mentioned above, can also be used, e.g. degraded starch, aldehyde starches, etc. Polyvinylpyrrolidone is also usable. Cellulose ethers such as carboxymethyl cellulose (Na salt), methyl cellulose, hydroxyalkyl cellulose, and mixed ethers such as methylhydroxyethyl cellulose, methylhydroxypropyl cellulose, methylcarboxymethyl cellulose, and mixtures thereof, are also often used, normally in quantities from 0.1 to 5 wt % based on the laundry detergent.
Although the aforesaid cellulose ethers have a good graying-inhibiting action, their use in aqueous liquid laundry detergents is subject to such narrow limits that in practice, they cannot be incorporated into them. The reason is that in addition to their graying-inhibitor effect that is relevant only in the context of use in washing methods, these cellulose ethers have comparatively low solubility in surfactant-containing systems, and have a pronounced thickening effect on aqueous systems. When they are incorporated into aqueous and in particular anionic surfactant-containing liquid laundry detergents at the concentrations desired for graying-inhibiting action, either the products obtained are generally no longer able to flow and be poured, and can be made usable for the consumer only with additional effort, for example preparation in individual dispensing portions packaged in water-soluble or tear-open water-insoluble fashion; or the cellulose ethers, especially after storage, are not completely dissolved in the aqueous liquid laundry detergent, which results not only in an inadequate aesthetic impression but also in non-uniform dispensing of the graying-inhibiting active substance when the detergent containing it is used.
(2) Description of Related Art, Including Information Disclosed Under 37 C.F.R. Sections 1.97 and 1.98
Not Applicable